1. Field of the Invention
This invention relates to a waterproof connector housing which mounts directly on a device and a method of producing the same. The connector housing includes a hood portion for fitting on a mating connector housing, an elastic seal ring provided inside the hood portion for forming a watertight seal between the waterproof connector housing and the mating connector housing, and an O-ring located at the proximal end of the hood portion facing the device for forming a watertight seal for the device.
2. Discussion of the Related Art
One conventional method of producing a watertight connector housing is disclosed in Japanese Patent Unexamined Publication No. 3-219578. FIG. 4 shows a housing A similar to one produced by this conventional method. The housing A includes a hood portion 3 of an enlarged size formed through a step portion 2.sub.1 on a housing body 1 for receiving a mating connector housing, and an elastic seal ring 4 integrated at a proximal end portion of the hood portion 3, that is, between the first step portion 2.sub.1 and a second step portion 2.sub.2. The elastic seal ring 4 has disengagement prevention portions 4a, and these disengagement prevention portions 4a fit snugly in through holes 2a formed through a proximal portion of the step portion 2.sub.1.
A disengagement prevention step portion 2a.sub.1 is formed on an inner surface of the through hole 2a, and is engaged with a disengagement prevention step portion 4a, of the associated disengagement prevention portion 4a, thereby preventing the elastic seal ring 4 from being disengaged when the mating connector housing is inserted and withdrawn. The housing body 1 has terminal receiving chambers 1a provided therein.
A method for producing the waterproof connector housing A similar to that disclosed in JP 3-219578 is described below. In a first step of the molding, the housing body 1 and the hood portion 3 are formed, and in a second step the elastic seal ring 4 is formed.
In the first step, an upper mold and a lower mold (both of which are not shown) are clamped together along the axis of the soon to be molded housing A, and the connector housing is injection molded using an ordinary method.
FIG. 5 shows the second step. An upper mold 6' and a lower mold 7', which has a cavity 9 corresponding to an elastic seal ring-forming portion, are clamped together, and an elastic material in the liquid state is introduced into the seal ring-forming portion (cavity 9) through a gate 8a of a runner 8, formed in the upper mold 6', and the through hole 2a.
In the first step, axial projections (not shown) are formed respectively on the first and second step portions 2.sub.1 and 2.sub.2, and a similar projection is formed on a peripheral portion disposed outwardly from the through holes 2a over an entire periphery thereof. When the upper and lower molds 6' and 7' are clamped together, these projections are compressed and crushed by the molds, and are held in intimate contact with the associated molds, thereby preventing the liquid elastic material of high fluidity from leaking.
In the above waterproof connector housing, no means are provided for forming a waterproof seal when the connector housing is directly mounted on a device. This type of connector housing will now be described with reference to FIGS. 6(a) to 6(c). FIG. 6(a) shows a type of connector housing which directly mounts on a device. A flange 2 is formed at a proximal end of a hood portion 3, and the flange 2 has through holes 2d for fastening screws for mounting the connector housing directly on the device. An O-ring receiving groove 2c, corresponding in size to an O-ring 5, is formed in the device-side surface of the proximal end of the hood portion 3. The depth of this O-ring receiving groove 2c is smaller than the thickness of the O-ring 5, and therefore the O-ring 5 is received in this O-ring receiving groove in such a manner that the O-ring 5 projects beyond the device-side surface of the proximal end of the hood portion 3. When this connector housing is fixedly secured to the device (see FIG. 6(b)), the O-ring is deformed to be held in intimate contact with the device, and prevents water from intruding through any gaps between the device and the connector housing.
An elastic seal ring 4 is provided inside the hood portion 3, and disengagement prevention portions 4a of this elastic seal ring fit snugly in through holes 2a. A step portion 4a1 of each disengagement prevention portion 4a is engaged with a step portion 2a1 on the inner surface of the associated through hole 2a, thereby preventing the elastic seal ring 4 from being disengaged.
In this type of connector housing which mounts directly on the device, the housing portion and the seal ring are molded in an integral manner, as described above, and although the disengagement of the seal ring is prevented by the disengagement prevention portions 4a, a few drawbacks have been encountered. First, when the molded product is removed from the mold, or the seal ring is disengaged out of position, the seal ring 4 may remain in the mold when disengaged (as indicated by an arrow in FIG. 6(c)) since the seal ring is made of an elastic material. In addition, the O-ring 5 is liable to be disengaged from the groove 2c as indicated by an arrow in FIG. 6(c). Therefore, when the waterproof connector housing is mounted on the device, it is necessary to confirm whether or not the O-ring 5 is in place, thus inviting a disadvantage due to the care that must be taken when handling the O-ring. Furthermore, the O-ring and the seal ring are produced separately from each other, thus undesirably increasing the cost.